Animal Research ERQ

Aim of Martinez and Kesner (1991)

To determine the role of the neurotransmitter acetylcholine in memory formation using rats in a maze-learning task.

Sample in Martinez and Kesner (1991)

Male laboratory rats; the exact number was not reported but was sufficient for three experimental conditions.

Procedure in Martinez and Kesner (1991)

Rats were trained to run a T-maze to find food. They were then divided into three groups: 1) One group received scopolamine, which blocks acetylcholine receptors. 2) The second group received physostigmine, which blocks the enzyme that breaks down acetylcholine, increasing its availability. 3) The third group was a control that received a saline solution. After injections, rats were tested on their ability to complete the maze.

Findings of Martinez and Kesner (1991)

Rats injected with scopolamine took longer to complete the maze and made more errors, while those injected with physostigmine completed it faster and more accurately than controls.

Conclusion of Martinez and Kesner (1991)

Acetylcholine plays a significant role in the formation of spatial memory. The findings support the idea that neurotransmitters influence learning and memory.

Relation of Martinez and Kesner (1991) to Antonova et al.

It provided foundational evidence for acetylcholine's role in memory, leading to human studies like Antonova, which explored similar mechanisms using fMRI and pharmacological blocking in healthy adults.

Aim of Weaver et al. (2004)

To investigate how maternal care influences the expression of stress-related genes in rats through epigenetic modification.

Sample in Weaver et al. (2004)

Laboratory rats separated based on whether their mothers exhibited high or low grooming and nurturing behaviours.

Procedure in Weaver et al. (2004)

Weaver compared rats raised by high-licking and low-licking mothers. They measured stress hormone responses and gene expression in the hippocampus. Cross-fostering was used to see whether the biological or adoptive mother's behaviour influenced the outcome.

Findings of Weaver et al. (2004)

Rats raised by low-nurturing mothers had higher stress responses and showed suppressed expression of the glucocorticoid receptor gene in the hippocampus due to epigenetic methylation. Cross-fostering revealed that maternal behaviour—not genetics—was the main factor.

Conclusion of Weaver et al. (2004)

Maternal care can alter gene expression related to stress response, showing an environmental impact on biological systems via epigenetics.

Relation of Weaver et al. (2004) to Caspi et al. (2003)

Weaver's animal findings about gene-environment interaction parallel Caspi's human study on how the 5-HTT gene moderates the effect of stressful life events on depression, showing that both genetic predispositions and environmental experiences influence behaviour.

Weaver's findings

Weaver's animal findings about gene-environment interaction parallel Caspi's human study on how the 5-HTT gene moderates the effect of stressful life events on depression, showing that both genetic predispositions and environmental experiences influence behaviour.

Aim of Albert et al. (1986)

To examine the relationship between testosterone levels and aggression in male rats.

Sample in Albert et al. (1986)

Male rats that were initially screened to be similar in size and aggression levels.

Procedure in Albert et al. (1986)

Rats were placed in cages and their aggression was measured. Then, they were divided into groups for surgical manipulation: 1) Castration (removing testes, thus eliminating testosterone production), 2) Castration followed by testosterone replacement, 3) Castration with placebo, 4) No surgery (control group). Aggression levels were measured again by recording dominant or aggressive behaviours such as biting or attacking when introduced to another rat.

Findings of Albert et al. (1986)

Castrated rats showed a significant drop in aggression. However, those that received testosterone replacement showed a return to normal levels of aggression, unlike the placebo group.

Conclusion of Albert et al. (1986)

Testosterone levels directly affect aggressive behaviour in rats, supporting the idea that hormones influence social behaviours.

Relation of Albert et al. to Carré et al. (2017)

Albert's study supports the biological basis of testosterone-linked aggression in animals, which complements Carré's human study that suggests testosterone modulates aggression particularly when combined with individual personality traits like dominance.

Strengths of animal research in psychology

- Allows for high experimental control over variables (e.g., hormone levels, neurotransmitters). - Ethical manipulations (e.g., lesioning, pharmacological interventions) that would not be allowed in human studies. - Can establish causal relationships, especially for biological mechanisms. - Enables longitudinal or developmental studies within shorter lifespans.

Limitations of animal research in psychology

- Questionable generalisability to humans due to species differences in brain structure and function. - Ethical concerns regarding harm, stress, or death of animals. - Artificial settings may not reflect natural behaviour. - Complex human behaviours (e.g., emotion, social norms) may not be fully modeled in animals.

Holistic evaluation of animal research in psychology

Animal research has greatly advanced our understanding of the biological underpinnings of behaviour, such as the role of neurotransmitters (Martinez & Kesner), epigenetics (Weaver), and hormones (Albert). These studies have led to ethical and methodologically sound human studies (e.g., Antonova, Caspi, Carré) that replicate or expand upon these findings. However, caution is needed in extrapolating results due to species and cognitive differences. While ethical frameworks exist (e.g., the 3Rs: Replacement, Reduction, Refinement), the moral justification of causing harm to animals for human benefit remains a topic of debate. A triangulated approach—using both human and animal research—yields the most balanced understanding of behaviour.